High frequency amplifier

Abstract

The present invention provides a high frequency amplifier using a power supply voltage regulate circuit for the purpose of compensating for variations in power supply voltage. The high frequency amplifier comprises three-stage power amplifiers which amplify an input signal and output the amplified signal, a bias circuit which supplies bias voltages for controlling these power amplifiers, a regulate circuit which compensates for variations in noise or gain with respect to the variations in the power supply voltage for driving the power amplifiers, etc. The regulate circuit holds constant an output voltage Vddc with respect to variations in power supply voltage Vdd and outputs the constant-held output voltage Vddc as a power supply voltage for the power amplifiers.

1. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof and capable of being shared between a GMSK system and an EDGE system; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the compensating circuit is a regulation circuit which holds constant an output voltage with respect to the variations in the power supply voltage.  
 
     
     
       2. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof and capable of being shared between a GMSK system and an EDGE system; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the compensating circuit is a first bias circuit which generates an output voltage having a reverse characteristic with respect to the variations in the power supply voltage and outputs the output voltage therefrom.  
 
     
     
       3. The high frequency amplifier according to  claim 2 , wherein the first bias circuit applies the output voltage having the reverse characteristic to a control terminal of at least the first-stage power amplifier of the plurality of stages of power amplifiers as a bias voltage. 
     
     
       4. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof and capable of being shared between a GMSK system and an EDGE system; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the power of the input signal is variable based on control of a gain control circuit connected to the outside.  
 
     
     
       5. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the compensating circuit is a regulation circuit which holds constant an output voltage with respect to the variations in the power supply voltage.  
 
     
     
       6. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the compensating circuit is a first bias circuit which generates an output voltage having a reverse characteristic with respect to the variations in the power supply voltage and outputs the output voltage therefrom.  
 
     
     
       7. The high frequency amplifier according to  claim 6 , wherein the first bias circuit applies the output voltage having the reverse characteristic to a control terminal of at least the first-stage power amplifier of the plurality of stages of power amplifiers as a bias voltage. 
     
     
       8. A high frequency amplifier, comprising:
 a plurality of stages of power amplifiers which amplify an input signal and output the same therefrom;  
 a bias circuit which supplies bias voltages for controlling the power amplifiers;  
 said input signal being inputted so as to be variable in power thereof; and  
 a compensating circuit which compensates for variations in noise or gain with respect to variations in power supply voltage for driving the power amplifiers,  
 wherein the power of the input signal is variable based on control of a gain control circuit connected to the outside.